Power supply system

ABSTRACT

The present teaching provides a power supply system capable of appropriately performing replacement or repairing of a component of a module where a problem occurs without stopping the entire operation, in a case where the problem occurs in of the module in a plurality of modules. The power supply system includes a plurality of sweep modules, a problem detector, an indicator, and a controller. Each sweep module includes a battery module and an electric power circuit module. The problem detector detects a problem for each sweep module. The indicator indicates a sweep module in which a problem is detected. In a case where a problem is detected in the sweep module (S 4:  YES), the controller causes the indicator to indicate a failure sweep module in which the problem is detected (S 5 ). The controller disconnects the failure sweep module from a main line, and continues sweep control (S 6  through S 8 ).

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of priority to Japanese Patent No.2018-222764 filed on Nov. 28, 2018. The entire contents of thisapplication are hereby incorporated herein by reference.

BACKGROUND 1. Technical Field

The present teaching relates to a power supply system including aplurality of modules each including a battery and a circuit.

2. Description of the Related Art

A power supply device known to date includes a plurality of modules eachincluding a battery and a circuit, and each of the modules is controlledto perform at least one of outputting of electric power to the outsideand storing of electric power input from the outside. For example, apower supply device described in Japanese Patent Application PublicationNo. 2018-74709 includes a plurality of battery circuit modules eachincluding a battery, a first switching device, and a second switchingdevice. The battery circuit modules are connected in series throughoutput terminals thereof. A control circuit for the power supply deviceoutputs gate signals for turning the first switching device and thesecond switching device on and off, to the battery circuit modules atevery given time. In this manner, a target level of electric power isoutput from the battery circuit modules.

SUMMARY

In a power supply device including modules each including a battery, oneor more of the modules might suffer from a problem (e.g., a problemoccurring in the battery in the module) in some cases. In such cases, ifa component suffering from the problem is replaced by another componentor is repaired, for example, with an operation of the entire powersupply device stopped, efficiency will decrease. In addition, inreplacing or repairing one or more of the modules, for example, it isdifficult for an operator to appropriately determine modules that needreplacement or other processes among the modules in the power supplydevice.

The present teaching provides a power supply system enabling appropriatereplacement or repairing of a component of a module suffering from aproblem without stopping an operation of the entire system in a casewhere a problem occurs in one or more of a plurality of modules.

In view of this, a power supply system in an aspect of this disclosureincludes: a main line; a plurality of sweep modules connected to themain line; a problem detector; an indicator; and a controller, whereineach of the sweep modules includes a battery module including at leastone battery, and an electric power circuit module including at least oneswitching device that switches a connection state between the batterymodules and the main line between connection and disconnection, theproblem detector is configured to detect a problem for each of the sweepmodules, the indicator is configured to enable instruction of one of thesweep modules in which a problem is detected, and the controller isconfigured to perform a first process of performing sweep control thatsequentially switches the battery module connected to the main lineamong the plurality of battery modules by outputting a gate signal forcontrolling the switching device to the electric power circuit module, asecond process of causing the indicator to indicate the sweep module inwhich the problem is detected, in a case where the problem detectordetects the problem in the sweep module, and a third process ofcontinuing the sweep control by excluding the sweep module in which theproblem is detected among the plurality of sweep modules whilecontinuously disconnecting, from the main line, the sweep module inwhich the problem is detected.

The power supply system of the configuration described above performssweep control of sequentially switching the sweep module connected tothe main line. When a problem is detected in one or more of theplurality of sweep modules, the controller continuously disconnects afailure sweep module in which the problem is detected, and excludes thefailure sweep module and continues the sweep control. In the sweepmodule disconnected from the main line, a component (e.g., a batterymodule) suffering from the problem is replaced or repaired with safety.That is, in the power supply system with the configuration describedabove, only the component of the sweep module suffering from the problemcan be replaced, for example, while operation of the entire system ismaintained. When a problem occurs in one or more batteries, the voltageof the batteries to be replaced can be easily reduced to a smaller valuethan that in the case of replacing all the batteries included in aplurality of sweep modules. Thus, safety can be easily obtained. Workingefficiency is higher than that in the case of replacing all thebatteries. In addition, the power supply system with the configurationdescribed above causes the indicator to indicate the sweep module inwhich the problem is detected. Thus, an operator can appropriately knowwhich one of the plurality of sweep modules needs replacement orrepairing, for example, of a component. Thus, in the power supply systemwith the configuration described above, replacement or repairing, forexample, of the component suffering from the problem is appropriatelyperformed without stopping of the entire operation.

In a preferred aspect of the power supply system disclosed here, theswitching device of the electric power circuit module includes a firstswitching device and a second switching device. The first switchingdevice is attached to the main line in series and attached to thebattery module in parallel. The second switching device is disposed in acircuit that connects the battery modules to the main line in series.The controller is configured to perform the sweep control bysequentially outputting, to each of the plurality of sweep modules, thegate signal for controlling alternate driving of turning the firstswitching device and the second switching device on and off, at everypredetermined delay time. In the third process, the controller outputs asignal for keeping an on-state of the first switching device and anoff-state of the second switching device to the sweep module in whichthe problem is detected so that the battery module in the sweep modulein which the problem is detected is continuously disconnected from themain line.

In this case, connection and disconnection of the battery module to themain line are appropriately switched for each sweep module. In addition,both the operation by sweep control and the operation of continuouslydisconnecting the battery module in the specific sweep module from themain line can be appropriately performed.

In a preferred aspect of the power supply system disclosed here,attachment to the electric power circuit module and detachment from theelectric power circuit module are performed using the battery moduleincluding the plurality of batteries as one unit. Thus, as compared to acase where the batteries suffering from a problem are replaced one byone, the number of jobs in replacing the batteries by an operator can bereduced.

In a preferred aspect of the power supply system disclosed here, thepower supply system further includes a replacement detector that detectsreplacement of the battery module in which the problem is detected byanother battery module. the controller is configured to perform a fourthprocess of performing the sweep control, by adding the sweep module inwhich the battery module is replaced to a connection target to the mainline, and finishing an instruction by the indicator, in a case where thereplacement detector detects replacement of the battery module. Thus,the operator can easily know that replacement of the battery modules canbe appropriately finished. In addition, input/output of electric powerto/from the outside appropriately continues with addition of thereplaced battery module.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 schematically illustrates a configuration of a power supplysystem 1.

FIG. 2 schematically illustrates a configuration of sweep modules 20.

FIG. 3 is an example of a timing chart in a sweep operation.

FIG. 4 is an example of a timing chart in a forced through operation.

FIG. 5 is a flowchart of an energizing control process performed by thepower supply system 1.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

One exemplary embodiment of the present disclosure will be describedhereinafter in detail with reference to the drawings. Matters notspecifically mentioned in the description but required for carrying outthe disclosure can be understood as matters of design variation of aperson skilled in the art based on related art in the field. The presentteaching can be carried out on the basis of the contents disclosed inthe description and common general knowledge in the field. In thedrawings, members and parts having the same functions are denoted by thesame reference numerals. In addition, dimensional relationship in eachdrawing does not reflect an actual dimensional relationship.

Schematic Overall Configuration

With reference to FIG. 1, an overall configuration of the power supplysystem 1 according to this exemplary embodiment will be schematicallydescribed. The power supply system 1 performs either output of electricpower to a distribution device 5 connected to a higher-order electricpower system 8, or storage of electric power input from the distributiondevice 5 (hereinafter also simply referred to as “input/output ofelectric power”). In this exemplary embodiment, a power conditioningsubsystem (PCS) is used as the distribution device 5, as an example. ThePCS has the function of exchanging electric power input from theelectric power system 8 to, for example, the power supply system 1 andelectric power output from, for example, the power supply system 1 tothe electric power system 8, between the power supply system 1, forexample, and the electric power system 8.

In a case where electric power is redundant in the electric power system8, the distribution device 5 outputs the redundant electric power to thepower supply system 1. In this case, the power supply system 1 storeselectric power input from the distribution device 5. In response to aninstruction from a higher-order system 6 for controlling thehigher-order electric power system 8, the power supply system 1 outputsthe electric power stored in the power supply system 1 to thedistribution device 5. In FIG. 1, the higher-order system 6 serves as asystem for controlling the electric power system 8 and the distributiondevice 5 and is disposed separately from the electric power system 8 andthe distribution device 5. Alternatively, the higher-order system 6 maybe incorporated in the electric power system 8 or the distributiondevice 5.

The power supply system 1 includes at least one string 10. The powersupply system 1 of this exemplary embodiment includes a plurality of (N:N≥2) strings 10 (10A, 10B, . . . , 10N). For convenience ofillustration, FIG. 1 shows only two strings 10A and 10B of the N strings10. Each of the strings 10 is a unit of inputting/outputting of electricpower to/from the distribution device 5. The strings 10 are connected tothe distribution device 5 in parallel. Electric power is input andoutput (electrification) between the distribution device 5 and each ofthe strings 10 through a main line 7.

Each of the strings 10 includes a string control unit (SCU) 11 and aplurality of (M: M≤2) sweep modules 20 (20A, 20B, . . . , 20M). Each ofthe sweep modules 20 includes a battery and a control circuit. The SCU11 is provided in each of the strings 10. The SCU 11 is a controller forintegrally controlling the sweep modules 20 included in one string 10.Each of the SCUs 11 communicates with a group control unit (GCU) 2serving as an electric power controller. The GCU 2 is a controller forintegrally controlling an entire group including the strings 10. The GCU2 communicates with the higher-order system 6 and each of the SCUs 11.Communication among the higher-order system 6, the GCU 2, and SCUs 11can employ various methods (e.g., at least one of communications such aswired communication, wireless communication, and communication through anetwork).

The configuration of the controller for controlling, for example, thestrings 10 and the sweep modules 20 may be changed. For example, the GCU2 may be disposed separately from the SCUs 11. Specifically, onecontroller may control both an entire group including at least onestring 10, and the sweep modules 20 included in the string 10.

Sweep Module

With reference to FIG. 2, the sweep modules 20 will be described indetail. Each of the sweep modules 20 includes a battery module 30, anelectric power circuit module 40, and a sweep unit (SU) 50.

The battery module 30 includes at least one battery 31. The batterymodule 30 of the exemplary embodiment includes a plurality of batteries31. The batteries 31 are connected to each other in series. In theexemplary embodiment, secondary batteries are used as the batteries 31.As the batteries 31, at least one of various secondary batteries (i.e.,nickel-metal hydride batteries, lithium ion batteries, or nickel-cadmiumbatteries) may be used. In the power supply system 1, a plurality oftypes of batteries 31 may be mixed. Of course, all the batteries 31 inthe battery module 30 may be of the same type.

A voltage detector 35 and a temperature detector 36 are attached to thebattery module 30. The voltage detector 35 detects a voltage of thebatteries 31 (batteries 31 connected in series in this exemplaryembodiment) included in the battery module 30. The temperature detector36 detects a temperature of the batteries 31 included in the batterymodule 30 or a temperature near the batteries 31. Various types ofdevices (e.g., a thermistor) for detecting a temperature may be used forthe temperature detector 36.

The battery module 30 is detachably attached to the electric powercircuit module 40. Specifically, in this exemplary embodiment,detachment from the electric power circuit module 40 and attachment tothe electric power circuit module 40 are performed using the batterymodule 30 including the plurality of batteries 31, as one unit. Thus, ascompared to a case where the batteries 31 included in the battery module30 are replaced one by one, the number of jobs in replacing thebatteries 31 by an operator can be reduced. In this exemplaryembodiment, the voltage detector 35 and the temperature detector 36 maybe replaced, separately from the battery module 30. Alternatively, atleast one of the voltage detector 35 and the temperature detector 36 maybe replaced together with the battery module 30.

The electric power circuit module 40 constitutes a circuit forappropriately implementing input/output of electric power in the batterymodule 30. In this exemplary embodiment, the electric power circuitmodule 40 includes at least one switching device for switching aconnection state between the battery module 30 and the main line 7between connection and disconnection. In this exemplary embodiment, theelectric power circuit module 40 includes an input/output circuit 43 forconnecting the battery module 30 to the main line 7, and a firstswitching device 41 and a second switching device 42 disposed in theinput/output circuit 43. The first switching device 41 and the secondswitching device 42 perform switching operations in accordance withsignals (e.g., gate signals) input from the sweep unit 50.

In this exemplary embodiment, as illustrated in FIG. 2, the firstswitching device 41 is attached to the main line 7 in series and isattached to the battery module 30 in parallel, in the input/outputcircuit 43. The second switching device 42 is attached to a portion ofthe input/output circuit 43 in which the battery module 30 is connectedto the main line 7 in series. The first switching device 41 includessource and drain disposed in a forward direction along a direction inwhich a discharge current flows in the main line 7. The second switchingdevice 42 includes source and drain disposed in a forward directionalong a direction in which a charge current flows in the battery module30, in the input/output circuit 43 through which the battery module 30is connected to the main line 7 in series. In this exemplary embodiment,the first switching device 41 and the second switching device 42respectively include body diodes 41 a and 42 a that are MOSFETs (e.g.,Si-MOSFETs) and oriented in a forward direction. Here, the body diode 41a of the first switching device 41 will be referred to as a first bodydiode as appropriate. The body diode 42 a of the second switching device42 will be referred to as a second body diode as appropriate.

The first switching device 41 and the second switching device 42 are notlimited to the example illustrated in FIG. 2. Various devices capable ofswitching a connection state between conduction and non-conduction maybe used as the first switching device 41 and the second switching device42. In this exemplary embodiment, MOSFETs (specifically, Si-MOSFETs) areused for both of the first switching device 41 and the second switchingdevice 42. Alternatively, devices except for MOSFETs (e.g., transistors)may be employed.

The electric power circuit module 40 includes an inductor 46 and acapacitor 47. The inductor 46 is disposed between the battery module 30and the second switching device 42. The capacitor 47 is connected to thebattery module 30 in parallel. In this exemplary embodiment, sincesecondary batteries are used as the batteries 31 of the battery module30, degradation of the batteries 31 caused by an increase in an internalresistance loss needs to be suppressed. In view of this, an RLC filteris constituted by the battery module 30, the inductor 46, and thecapacitor 47 in order to level a current.

The electric power circuit module 40 includes the temperature detector48. The temperature detector 48 is disposed to detect heat generation ofat least one of the first switching device 41 and the second switchingdevice 42. In this exemplary embodiment, the first switching device 41,the second switching device 42, and the temperature detector 48 areincorporated in one board. Thus, the board itself is replaced with a newone at the time when a failure is found in one of the first switchingdevice 41 and the second switching device 42. Thus, in this exemplaryembodiment, one temperature detector 48 is disposed near the firstswitching device 41 and the second switching device 42 so that thenumber of components is reduced. The temperature detector for detectinga temperature of the first switching device 41 and a temperaturedetector for detecting a temperature of the second switching device 42may be provided separately. Various devices for detecting a temperature(e.g., a thermistor) may be used as the temperature detector 48.

As illustrated in FIGS. 1 and 2, the battery modules 30 in the strings10 are connected to the main line 7 in series through the electric powercircuit modules 40. The battery modules 30 are connected to ordisconnected from the main line 7 by appropriately controlling the firstswitching device 41 and the second switching device 42 of the electricpower circuit modules 40. In the example configuration of the electricpower circuit module 40 illustrated in FIG. 2, when the first switchingdevice 41 is turned off and the second switching device 42 is turned on,the battery module 30 is connected to the main line 7. When the firstswitching device 41 is turned on and the second switching device 42 isturned off, the battery module 30 is disconnected from the main line 7.

A sweep unit (SU) 50 is a control unit incorporated in each of the sweepmodule 20 in order to perform various types of control concerning thesweep module 20. The sweep unit 50 will be also referred to as a sweepcontrol unit. Specifically, the sweep unit 50 outputs a signal fordriving the first switching device 41 and the second switching device 42in the electric power circuit module 40. The sweep unit 50 notifies ahigher-order controller (SCU 11 illustrated in FIG. 1 in this exemplaryembodiment) of the state of the sweep module 20 (e.g., a voltage of thebattery module 30, temperatures of the batteries 31, and thetemperatures of the switching devices 41 and 42). The sweep unit 50 isincorporated in each of the sweep modules 20 of the string 10. The sweepunits 50 incorporated in the sweep modules 20 of the string 10 aresequentially connected, and sequentially propagates a gate signal GSoutput from the SCU 11. As illustrated in FIG. 2, in this exemplaryembodiment, the sweep unit 50 includes an SU processor 51, adelay/selection circuit 52, and a gate driver 53.

The SU processor 51 is a controller for various processes in the sweepunit 50. A microcomputer, for example, may be used as the SU processor51. The SU processor 51 receives detection signals from the voltagedetector 35, the temperature detector 36, and the temperature detector48. The SU processor 51 inputs and outputs various types of signalsto/from a higher-order controller (the SCU 11 of the string 10 in thisexemplary embodiment).

A signal input from the SCU 11 to the SU processor 51 includes a forcedthrough signal CSS and a forced connection signal CCS. The forcedthrough signal CSS is a signal for instructing disconnection of thebattery module 30 from the main line 7 (see FIG. 1) extending from thedistribution device 5 to the string 10. That is, the sweep module 20that has received the forced through signal CSS does not perform (passesthrough) an operation for inputting and outputting electric componentto/from the distribution device 5. The forced connection signal CCS is asignal for instructing maintenance of connection of the battery module30 to the main line 7.

A gate signal GS is input to the delay/selection circuit 52. The gatesignal (PWM signal in this exemplary embodiment) GS is a signal forcontrolling a repetitive switching operation between an on state and anoff state of each of the first switching device 41 and the secondswitching device 42. The gate signal GS is a pulse signal in which onand off are alternately repeated. First, the gate signal GS is inputfrom the SCU 11 (see FIG. 1) to the delay/selection circuit 52 in one ofthe sweep modules 20. Next, the gate signal GS is sequentiallypropagated from the delay/selection circuit 52 in one sweep module 20 tothe delay/selection circuit 52 in another sweep module 20.

In the string 10, sweep control shown in FIGS. 3 and 4 is performed.FIG. 3 is an example of a timing chart in a sweep operation.Specifically, FIG. 3 shows an example of a relationship between aconnection state of each sweep module 20 and a voltage output to thedistribution device 5 in a case where all the sweep modules 20 perform asweep operation. FIG. 4 is an example of a timing chart in a forcedthrough operation. Specifically, FIG. 4 shows an example of arelationship between a connection state of each sweep module 20 and avoltage output to the distribution device 5 in a case where at least oneof the sweep modules 20 performs a forced through operation.

In the sweep control performed in the string 10, in the plurality of(e.g., M) sweep modules 20 incorporated in the string 10, the number (m)of sweep modules 20 that turn on at the same time is defined. The gatesignal GS in the sweep control is constituted by, for example, a pulsewaveform. In the gate signal GS, signal waveforms for connecting thebattery module 30 to the main line 7 and signal waveforms fordisconnecting the battery module 30 from the main line 7 are preferablyalternately arranged, for example. In the gate signal GS, the signalwaveform for connecting the battery modules 30 to the main line 7preferably includes the number of battery modules 30 connected to themain line 7 in a predetermined period T in which the string 10 is swept.The signal waveform for disconnecting the battery modules 30 from themain line 7 includes a given number of battery modules 30 that need tobe disconnected from the main line 7 out of the battery modules 30incorporated in the string 10. The signal waveform for connecting thebattery modules 30 to the main line 7 and the signal waveform fordisconnecting the battery modules 30 from the main line 7 are adjustedas appropriate with respect to, for example, the shape of the waveforms.

In the string 10 of the exemplary embodiment, the M sweep modules 20 areconnected in series in the order of sweep modules 20A, 20B, . . . , 20Mfrom the side toward the distribution device 5. The side toward thedistribution device 5 will be hereinafter referred to as an upstreamside, and the side away from the distribution device 5 will behereinafter referred to as a downstream side. First, a gate signal GS isinput from the SCU 11 to the delay/selection circuit 52 of the sweepunit 50 in the sweep module 20A at the most upstream side. Next, thegate signal GS is propagated from the delay/selection circuit 52 in thesweep module 20A to the delay/selection circuit 52 in the sweep module20B adjacent to the sweep module 20A at the downstream side. Propagationof the gate signal to the adjacent downstream sweep module 20 issequentially repeated to the most downstream sweep module 20M.

Here, the delay/selection circuit 52 can delay the pulsed gate signal GSinput from the SCU 11 or the upstream sweep module 20 by a predetermineddelay time and propagate the resulting gate signal GS to the downstreamsweep module 20. In this case, a signal indicating the delay time isinput from the SCU 11 to the sweep unit 50 (e.g., the SU processor 51 inthe sweep unit 50 in this exemplary embodiment). Based on the delay timeindicated by the signal, the delay/selection circuit 52 delayspropagation of the gate signal GS. The delay/selection circuit 52 mayalso propagate the input gate signal GS to the downstream sweep module20 without delay.

The gate driver 53 drives switching operations of the first switchingdevice 41 and the second switching device 42. The delay/selectioncircuit 52 outputs a signal for controlling driving of the gate driver53, to the gate driver 53. The gate driver 53 outputs a control signalto each of the first switching device 41 and the second switching device42. In the case of connecting the battery module 30 to the main line 7,the gate driver 53 outputs control signals for turning the firstswitching device 41 off and the second switching device 42 on. In thecase of disconnecting the battery module 30 from the main line 7, thegate driver 53 outputs control signals for turning the first switchingdevice 41 on and the second switching device 42 off.

The delay/selection circuit 52 of the exemplary embodiment is controlledby a control device such as the SCU 11, and selectively performs a sweepoperation, a forced through operation, and a forced connectionoperation.

For example, in the sweep operation, the first switching device 41 andthe second switching device 42 are operated based on the gate signal GS.The battery modules 30 included in the string 10 are connected to themain line 7 in a predetermined order, and are disconnected from the mainline 7 in a predetermined order. Consequently, in the string 10, apredetermined number of battery modules 30 are driven while being alwaysconnected to the main line 7 with the battery module 30 connected to themain line 7 being sequentially switched in a short control period. Withthis sweep operation, in the string 10, while the battery module 30connected to the main line 7 is sequentially switched in a short controlperiod, the string 10 functions as if the string 10 is one batteryassembly in which a predetermined number of battery modules 30 areconnected in series. To obtain the sweep operation, the sweep modules 20in the string 10 are controlled by the SCU 11. In this control, the SCU11 outputs the gate signal GS to the string 10, and outputs a controlsignal to the SU processor 51 included in each of the sweep modules 20.An example of the sweep operation will be described later in detail withreference to FIGS. 3 and 4.

In the sweep operation, the delay/selection circuit 52 outputs the inputgate signal GS to the gate driver 53 without change, delays the gatesignal GS by a delay time, and propagates the resulting gate signal GSto the downstream sweep module 20. Consequently, the battery modules 30of the sweep modules 20 under the sweep operation are sequentiallyconnected to the main line 7 and are sequentially disconnected from themain line 7 while the timings of each of the connection and thedisconnection are shifted from one another in the string 10.

In the forced through operation, the delay/selection circuit 52 keepsthe first switching device 41 on, independently of the input gate signalGS, and outputs a signal for keeping the second switching device 42 off,to the gate driver 53. Consequently, the battery module 30 in the sweepmodule 20 under the forced through operation is disconnected from themain line 7. The delay/selection circuit 52 of the sweep module 20 underthe forced through operation does not delay the gate signal GS andpropagates the gate signal GS to the downstream sweep module 20.

During the forced connection operation, the delay/selection circuit 52keeps the first switching device 41 off, independently of the input gatesignal GS, and outputs a signal for keeping the second switching device42 on, to the gate driver 53. Consequently, the battery module 30 of thesweep module 20 under the forced connection operation is alwaysconnected to the main line 7. The delay/selection circuit 52 of thesweep module 20 under the forced connection operation does not delay thegate signal GS, and propagates the gate signal GS to the downstreamsweep module 20.

The delay/selection circuit 52 may be configured as one integratedcircuit having necessary functions as described above. Thedelay/selection circuit 52 may be a combination of a circuit fordelaying the gate signal GS and a circuit for selectively sending thegate signal GS to the gate driver 53. An example configuration of thedelay/selection circuit 52 of the exemplary embodiment will be describedbelow.

In the exemplary embodiment, as illustrated in FIG. 2, thedelay/selection circuit 52 includes a delay circuit 52 a and a selectioncircuit 52 b. The gate signal GS input to the delay/selection circuit 52is input to the delay circuit 52 a. The delay circuit 52 a delays thegate signal GS by a predetermined delay time, and outputs the resultinggate signal GS to the selection circuit 52 b. In another case, the gatesignal GS input to the delay/selection circuit 52 is output to theselection circuit 52 b through another route not passing through thedelay circuit 52 a. The selection circuit 52 b receives an instructionsignal from the SU processor 51, and produces an output in accordancewith the instruction signal.

In a case where the instruction signal from the SU processor 51instructs performing a sweep operation, the selection circuit 52 boutputs the input gate signal GS to the gate driver 53 of this sweepmodule 20 without change. The gate driver 53 outputs a control signal tothe electric power circuit module 40, turns the first switching device41 off, turns the second switching device 42 on, and connects thebattery module 30 to the main line 7. On the other hand, the selectioncircuit 52 b outputs the delayed gate signal GS to the delay/selectioncircuit 52 in the sweep module 20 at a downstream side adjacent to thesweep module 20 which input gate signal GS. That is, in a case where thebattery module 30 is connected to the main line 7 in the sweepoperation, the gate signal GS delayed by the predetermined delay time issent to the adjacent downstream sweep module 20.

In a case where the instruction signal from the SU processor 51 is theforced through signal CSS, the selection circuit 52 b outputs a signalfor passing through the battery module 30, to the gate driver 53. Bycontinuing the forced through signal CSS, the battery module 30 in thesweep module 20 that has received the forced through signal CSS is keptdisconnected from the main line 7. In this case, the selection circuit52 b outputs a gate signal GS input to the selection circuit 52 bthrough a route not passing through the delay circuit 52 a, to theadjacent downstream sweep module 20.

In a case where the instruction signal from the SU processor 51 is theforced connection signal CCS, the selection circuit 52 b outputs, to thegate driver 53, a signal for connecting the battery module 30 to themain line 7. That is, the gate driver 53 turns the first switchingdevice 41 off, turns the second switching device 42 on, and connects thebattery module 30 to the main line 7. By continuing the forcedconnection signal CCS, the battery module 30 is kept connected to themain line 7. In this case, the selection circuit 52 b outputs a gatesignal GS input to the selection circuit 52 b through a route notpassing through the delay circuit 52 a, to the adjacent downstream sweepmodule 20.

As illustrated in FIGS. 1 and 2, in this exemplary embodiment, theplurality of sweep units 50 (specifically a plurality of delay/selectioncircuits 52) included in one string 10 are connected sequentially toeach other in a daisy chain mode. Consequently, the gate signal GS inputto one sweep unit 50 from the SCU 11 is sequentially propagated amongthe plurality of sweep units 50. Thus, processing in the SCU 11 can beeasily simplified, and an increase in the number of signals can beeasily suppressed. Alternatively, the SCU 11 may output a gate signal GSto each of the plurality of sweep units 50 independently of each other.

The sweep unit 50 includes an indicator 57. The indicator 57 notifies anoperator of a state of the sweep module 20 including the battery module30, the electric power circuit module 40, and other components, forexample. The indicator 57 is capable of notifying the operator that aproblem (e.g., a failure or degradation of the batteries 31) is detectedin the battery module 30 in the sweep module 20 (i.e., the batterymodule 30 needs to be replaced).

As an example, an LED that is a light-emitting device is used for theindicator 57 of the exemplary embodiment. Alternatively, a device exceptfor an LED (e.g., a display) may be used as the indicator 57. A devicefor outputting voice (e.g., a loudspeaker) may be used as the indicator57. The indicator 57 may notify the operator of the state of the sweepmodule 20 by driving a member by an actuator (e.g., a motor or asolenoid). The indicator 57 is preferably configured to indicate a stateby various methods in accordance with the state of the sweep module 20.

In the exemplary embodiment, operation of the indicator 57 is controlledby the SU processor 51 in the sweep unit 50. Alternatively, theoperation of the indicator 57 may be controlled by a controller (e.g.,the SCU 11) except for the SU processor 51

In the exemplary embodiment, the indicator 57 is disposed for each ofthe sweep unit 50. Thus, the operator can easily identify the sweepmodule 20 whose state is notified by the indicator 57 among theplurality of sweep modules 20. Alternatively, the configuration of theindicator 57 may be changed. For example, separately from the indicator57 disposed for each sweep unit 50, or together with the indicator 57, astate notifier for notifying a summary of states of the plurality ofsweep modules 20 may be disposed. In this case, the state notifier maydisplay a summary of the states of the plurality of sweep modules 20(e.g., whether a problem occurs or not) on one monitor.

Sweep Control

Sweep control performed in the string 10 will be described. Here, thesweep control is a control for causing the battery modules 30 in thestring 10 to perform a sweep operation. In the sweep control performedin the string 10, the SCU 11 outputs a pulsed gate signal GS. Theswitching devices 41 and 42 in the sweep modules 20 of the strings 10are switched between on and off to be driven as appropriate.Consequently, connection of the battery module 30 to the main line 7 anddisconnection of the battery module 30 from the main line can beswitched from each other at high speed for each of the sweep modules 20.In addition, the string 10 can delay the gate signal GS input to theX-th sweep module 20 from the upstream side with respect to the gatesignal GS input to the (X−1)th sweep module 20. Consequently, among theM sweep modules 20 included in the string 10, m (m<M) sweep modules 20connected to the main line 7 are sequentially switched. Accordingly, theplurality of battery modules 30 included in the string 10 are connectedto the main line 7 in a predetermined order and disconnected from themain line 7 in a predetermined order. Then, a state as if apredetermined number of battery modules 30 are always connected to themain line 7 can be obtained. With the sweep operation, the string 10functions as one battery assembly in which a predetermined number ofbattery modules 30 are connected in series.

FIG. 3 is a timing chart showing an example of a relationship between aconnection state of each sweep module 20 and a voltage output to thedistribution device 5 in a case where all the sweep modules 20 includedin the string 10 are caused to perform a sweep operation. The number Mof the sweep modules 20 included in one string 10 may be changed asappropriate. In the example shown in FIG. 3, one string 10 includes fivesweep modules 20, and all the five sweep modules 20 are caused toperform the sweep operation.

In the example shown in FIG. 3, a VH instruction signal for setting avoltage VH[V] to be output to the distribution device 5 at 100 V isinput to the SCU 11 of the string 10. A voltage Vmod [V] of the batterymodule 30 in each of the sweep modules 20 is 43.2 V. A delay time DL[μsec] for delaying the gate signal GS is set as appropriate inaccordance with requirements for the power supply system 1. A period T(i.e., a period for connection or disconnection of the sweep module 20)of the gate signal GS is a value obtained by multiplying, by a delaytime DL, the number P (≤M) of sweep modules 20 caused to perform thesweep operation. Thus, if the delay time DL is long, the frequency ofthe gate signal GS is a low frequency. On the other hand, if the delaytime DL is short, the frequency of the gate signal GS is a highfrequency. In the example shown in FIG. 3, the delay time DL is set at2.4 μsec. Thus, the period T of the gate signal GS is “2.4 μsec×5=12μsec.”

In this exemplary embodiment, the battery module 30 of the sweep module20 in which the first switching device 41 is off and the secondswitching device 42 is on, is connected to the main line 7. That is,when the first switching device 41 is turned off and the secondswitching device 42 is turned on, the capacitor 47 connected to thebattery module 30 in parallel is connected to the input/output circuit43, and electric power is input or output. The sweep unit 50 of thesweep module 20 connects the battery module 30 to the main line 7 whilethe gate signal GS is on. On the other hand, the battery module 30 ofthe sweep module 20 in which the first switching device 41 is off andthe second switching device 42 is on, is disconnected from the main line7. The sweep unit 50 disconnects the battery module 30 from the mainline 7 while the gate signal GS is off.

When the first switching device 41 and the second switching device 42are turned on at the same time, a short circuit occurs. Thus, in thecase of switching the first switching device 41 and the second switchingdevice 42, the sweep unit 50 switches one of the devices from on to off,and after a lapse of a small standby time, then switches the otherdevice from off to on. As a result, occurrence of a short circuit isprevented.

Supposing a VH instruction value instructed by the VH instruction signalis VH_com, voltage of each battery module 30 is Vmod, the number ofsweep modules 20 to perform a sweep operation (i.e., the number of sweepmodules 20 as connection targets to the main line 7 in the sweepcontrol) is P. In this case, in the gate signal GS, a duty ratiooccupied by an on-period in the period T is obtained by“VH_com/(Vmod×P).” In the example shown in FIG. 3, the duty ratio of thegate signal GS is about 0.46. Strictly, the duty ratio is shifted underthe influence of the standby time for preventing occurrence of a shortcircuit. Thus, the sweep unit 50 may correct the duty ratio by using afeedback process or a feedforward process.

As shown in FIG. 3, when the sweep control starts, one (e.g., the sweepmodule 20 of No. 1 at the most upstream side in the example shown inFIG. 3) of P sweep modules 20 comes to be in a connected state.Thereafter, after a lapse of a delay time DL, the next sweep module 20(e.g., the second sweep module 20 of No. 2 from the upstream side in theexample shown in FIG. 3) also comes to be in a connected state. In thisstate, a voltage VH output to the distribution device 5 is the sum ofvoltages of the two sweep modules 20, and does not reach a VHinstruction value. Subsequently, after a lapse of the delay time DL, thesweep module 20 of No. 3 comes to be in a connected state. In thisstate, the number of sweep modules 20 connected to the main line 7 isthree, that is, No. 1 through No. 3. Thus, the voltage VH output to thedistribution device 5 is the sum of voltages of the three sweep modules20, which is larger than the VH instruction value. Subsequently, whenthe sweep modules 20 of No. 1 is disconnected from the main line 7, thevoltage VH returns to the sum of the voltages of the two sweep modules20. After a lapse of the delay time DL from the start of connection ofNo. 3, the sweep module 20 of No. 4 comes to be in a connected state.Consequently, the number of sweep modules 20 connected to the main line7 is three, that is, No. 2 through No. 4. As described above, with thesweep control, m (three in FIG. 3) sweep modules 20 connected to themain line 7 out of the M (five in FIG. 3) sweep modules 20 aresequentially switched.

As shown in FIG. 3, the VH instruction value is not divisible by thevoltage Vmod of each battery module 30 in some cases. In such cases, thevoltage VH output to the distribution device 5 varies. The voltage VH,however, is levelled by the RLC filter, and is output to thedistribution device 5. In a case where electric power input from thedistribution device 5 is stored in the battery module 30 of each of thesweep modules 20, the connection state of the sweep module 20 iscontrolled, in a manner similar to the timing chart of FIG. 3.

Forced Through Operation

With reference to FIG. 4, description will be given on control in a casewhere one or more of the sweep modules 20 are caused to perform a forcedthrough operation and the other sweep module(s) 20 is/are caused toperform a sweep operation. As described above, the sweep module 20instructed to perform a forced through operation keeps a state in whichthe battery module 30 is disconnected from the main line 7. The exampleshown in FIG. 4 is different from the example shown in FIG. 3 in thatthe sweep module 20 of No. 2 is caused to perform a forced throughoperation. That is, in the example shown in FIG. 4, the number of sweepmodules 20 caused to perform a sweep operation (i.e., the number ofsweep modules 20 as connection targets to the main line 7) P is four inthe five sweep modules 20 included in one string 10. The VH instructionvalue, the voltage Vmod of each battery module 30, and the delay time DLare the same as those in the example shown in FIG. 3 In the exampleshown in FIG. 4, a period T of the gate signal GS is “2.4 μsec×4=9.6μsec.” A duty ratio of the gate signal GS is about 0.58.

As shown in FIG. 4, in the case where one or more of the sweep modules20 (e.g., the sweep module 20 of No. 2 in FIG. 4) are caused to performthe forced through operation, the number P of sweep modules 20 caused toperform the sweep operation is smaller than that in the example shown inFIG. 3. However, the string 10 adjusts the period T of the gate signalGS and the duty ratio of the gate signal GS in accordance with thedecrease of the number P of the sweep modules 20 caused to perform thesweep operation. Consequently, a waveform of the voltage VH output tothe distribution device 5 is the same as the waveform of the voltage VHshown in FIG. 3 as an example. Thus, even in the case of increasing orreducing the number P of the sweep modules 20 caused to perform thesweep operation, the string 10 can output an instructed voltage VH tothe distribution device 5 as appropriate.

In a case where a problem (e.g., degradation or a failure) occurs in thebattery 31 of one of the sweep modules 20, for example, the string 10 iscapable of causing the sweep module 20 including the battery 31suffering from the problem to perform the forced through operation.Thus, the string 10 is capable of outputting an instructed voltage VH tothe distribution device 5 appropriately by using the sweep modules 20suffering from no problems. In addition, it is possible for the operatorto replace the battery module 30 including the battery 31 suffering froma problem (i.e., the battery module 30 of the sweep module 20 caused toperform the forced through operation) while allowing the string 10 tooperate normally. In other words, in the power supply system 1 of theexemplary embodiment, it is unnecessary to stop an operation of theentire string 10 in replacing the battery module 30.

In a case where one or more of the sweep modules 20 are caused toperform the forced connection operation, the connection states of thesesweep modules 20 caused to perform the forced connection operation is analways connection state. For example, in the case of causing the sweepmodule 20 of No. 2 shown in FIG. 4 is caused to perform not the forcedthrough operation but the forced connection operation, the connectionstate of No. 2 is kept not “disconnected” but “connected.”

In the case where the power supply system 1 includes a plurality ofstrings 10, the sweep control is performed in each of the strings 10.The controller for integrally controlling the entire power supply system1 (the GCU 2 in this exemplary embodiment) controls operations of theplurality of strings 10 in order to satisfy an instruction from thehigher-order system 6. For example, in a case where only one string 10cannot satisfy a VH instruction value required by the higher-ordersystem 6, the GCU 2 causes the plurality of strings 10 to outputelectric power so that the VH instruction value is satisfied.

String

With reference to FIG. 1, an entire configuration of the strings 10 andthe power supply system 1 will be described in detail. As describedabove, each string 10 includes the SCU 11 and the plurality of sweepmodules 20 connected to the main line 7 in series through the electricpower circuit modules 40. The main line 7 of the string 10 is connectedto a bus line 9 extending from the distribution device 5. The string 10includes, from the side toward the distribution device 5 (upstream side)in the main line 7, a bus line voltage detector 21, a system breaker(also referred to as a system main relay (SMR) as appropriate) 22, astring capacitor 23, a string current detector 24, a string reactor 25,and a string voltage detector 26. Arrangement of one or more of themembers may be changed. For example, the system breaker 22 may bedisposed downstream of the string capacitor 23.

The bus line voltage detector 21 detects a voltage on the bus line 9extending from the distribution device 5 to the string 10. The systembreaker 22 switches the connection state between the string 10 and thedistribution device 5 between connection and disconnection. In thisexemplary embodiment, the system breaker 22 is driven in accordance witha signal input from the SCU 11. The string capacitor 23 and the stringreactor 25 constitute an RLC filter to thereby level a current. Thestring current detector 24 detects a current flowing between the string10 and the distribution device 5. The string voltage detector 26 detectsa voltage as the sum of voltages of the plurality of sweep modules 20connected to the main line 7 in series in the string 10, that is, astring voltage of the string 10.

In the configuration illustrated in FIG. 1, the system breaker 22includes a switch 22 a and a fuse 22 b. The switch 22 a is a device forconnecting and disconnecting the string 10 to/from the distributiondevice 5. The switch 22 a will be also referred to as a string switch,as appropriate. When the switch 22 a is turned on, the main line 7 ofthe string 10 and the bus line 9 of the distribution device 5 areconnected to each other. When the switch 22 a is turned off, the string10 is disconnected from the distribution device 5. The switch 22 a iscontrolled by the SCU 11 for controlling the string 10. By operating theswitch 22 a, the string 10 is disconnected and connected from/to thedistribution device 5, as appropriate. The fuse 22 b is a device forstopping a flow of an unexpected large current in terms of design of thestring 10 in the main line 7 of the string 10 in a case where the largecurrent flows in the main line 7. The fuse 22 b will be referred to as astring fuse, as appropriate.

Here, if batteries satisfying the same standard are incorporated in onebattery module 30, the voltage of the battery module 30 increases as thenumber of incorporated batteries increases. On the other hand, if thevoltage of the battery module 30 is high, danger arises in handling byan operator, and the system is heavy. In view of this, one batterymodule 30 preferably includes a large number of batteries within therange where the voltage of the battery module 30 is at such a level thata touch by a person with the module 30 in a fully charged state does notcause a serious accident (e.g., less than 60 V, preferably less than 42V) and the battery module 30 has such a weight that one operator canreplace the systems. The battery module 30 incorporated in the string 10does not need to be constituted by exactly the same type of batteries,and the number of batteries incorporated in one battery module 30 may bedetermined in accordance with the type and standard of batteriesincorporated in the battery module 30. The string 10 is configured suchthat the sweep modules 20 including the battery modules 30 are connectedin series to thereby enable an output of a predetermined voltage. Thepower supply system 1 is configured to enable an output of apredetermined level of electric power for connection to the electricpower system 8 by combining the plurality of strings 10.

In this exemplary embodiment, the distribution device 5 to which thestrings 10 of the power supply system 1 are connected includessub-distribution devices 5A and 5B respectively connected to the strings10A and 10B. The strings 10A and 10B connected to the sub-distributiondevices 5A and 5B are connected in parallel through the sub-distributiondevices 5A and 5B. The distribution device 5 controls distribution ofelectric power input from the electric power system 8 to the strings 10Aand 10B, integration of electric power output from the strings 10A and10B to the electric power system 8, and so forth through thesub-distribution devices 5A and 5B connected to the strings 10. Thedistribution device 5 and the sub-distribution devices 5A and 5B arecontrolled such that the power supply system 1 including the strings 10functions as one power supply device as a whole by cooperation of theGCU 2 connected to the higher-order system 6 and the SCUs 11 forcontrolling the strings 10.

For example, in this exemplary embodiment, the downstream side of thedistribution device 5, that is, a side toward the strings 10A and 10B,is controlled by a direct current (DC). The upstream side of thedistribution device 5, that is, the electric power system 8, iscontrolled by an alternating current (AC). The voltages of the strings10A and 10B are controlled to be substantially balanced with respect tothe voltage of the electric power system 8, through the distributiondevice 5. When the voltages of the strings 10A and 10B are controlled tobe lower than the voltage of the electric power system 8, a currentflows from the electric power system 8 to the strings 10A and 10B. Atthis time, when sweep control is performed in each of the strings 10Aand 10B, the battery modules 30 are charged as appropriate. When thevoltages of the strings 10A and 10B are controlled to be higher than thevoltage of the electric power system 8, a current flows form the strings10A and 10B to the electric power system 8. At this time, when sweepcontrol is performed in each of the strings 10A and 10B, the batterymodules 30 are discharged as appropriate. The distribution device 5 maybe controlled such that the voltages of the strings 10A and 10B are keptto be balanced with respect to the voltage of the electric power system8 so that substantially no current flows in the strings 10A and 10B. Inthis exemplary embodiment, such control can be performed for each of thesub-distribution devices 5A and 5B to which the strings 10A and 10B areconnected. For example, control may be performed such that the voltageof each of the strings 10A and 10B is adjusted so that substantially nocurrent flows in one of the strings 10A and 10B connected to thedistribution device 5.

In the power supply system 1, the number of strings 10 connected to thedistribution device 5 in parallel is increased so that the capacity ofthe power supply system 1 as a whole can be increased. For example, inthe power supply system 1, a large-size system capable of producing anoutput that can absorb an abrupt increase in demand of the electricpower system 8 and of compensating for a sudden power shortage of theelectric power system 8 can be assembled. For example, an increase inthe capacity of the power supply system 1 can use large redundantelectric power of the electric power system 8 for charging of the powersupply system 1 as appropriate. For example, in a case where an outputof an electric power station is redundant in a time zone where electricpower demand is low at midnight or a case where the amount of powergeneration rapidly increases in a large solar power station, the powersupply system 1 can absorb redundant electric power through thedistribution device 5. In contrast, in a case where demand for electricpower rapidly increases in the electric power system 8, requiredelectric power can be output from the power supply system 1 to theelectric power system 8 through the distribution device 5 asappropriate, in accordance with an instruction from the higher-ordersystem 6. In this manner, the power supply system 1 compensates for anelectric power shortage of the electric power system 8 as appropriate.

In the power supply system 1, all the plurality of battery modules 30incorporated in the strings 10 do not need to be always connected. Sincethe forced through operation can be performed for each of the batterymodules 30 as described above, when an abnormality occurs in one of thebattery modules 30, this battery module 30 can be disconnected from thesweep control of the string 10. Thus, in the power supply system 1,batteries used for the battery modules 30 do not need to be unused newbatteries.

For example, secondary batteries used as a drive power source for anelectric vehicle such as a hybrid vehicle or an electric automobile canbe reused. Even if a secondary battery used as such a drive power supplyis used for about 10 years, this secondary battery can sufficientlyfunction as a secondary battery. In the power supply system 1, thebattery module 30 showing abnormality can be immediately disconnected,and thus, batteries can be incorporated after confirmation that thebatteries have necessary given functions. Secondary batteries used as apower for driving an electric vehicle sequentially reach periods forcollection. The power supply system 1 can also incorporate secondarybatteries corresponding to 10,000 electric vehicles, and is expected toabsorb a considerable amount of collected secondary batteries. It isunexpected when functions of the secondary batteries used as a powersupply for driving electric vehicles degrade. In a case where suchsecondary batteries are reused for the battery modules 30 of the powersupply system 1, it is impossible to expect when a problem occurs in thebattery modules 30.

However, in the power supply system 1 proposed here, the battery modules30 can be appropriately disconnected through the sweep modules 20. Thus,even when a problem occurs in the battery module 30 or a secondarybattery incorporated in the battery module 30, it is unnecessary to stopthe entire power supply system 1.

Energizing Control Process

In an energizing control process, a process for appropriately replacingthe battery module 30 suffering from a problem while performing sweepcontrol in one string 10 is performed. With reference to FIG. 5, anenergizing control process performed by the power supply system 1 of theexemplary embodiment will be described.

The energizing control process exemplified in the exemplary embodimentis performed by the SCUs 11 serving as controllers (control units)included in the strings 10. When each of the SCUs 11 receives a startinstruction of sweep control in the string 10 from the GCU 2, the SCU 11starts the energizing control process exemplified in FIG. 5. Thecontroller for performing the energizing control process is not limitedto SCUs 11. For example, the GCU 2 may perform the energizing controlprocess, or a controller for performing an energizing control processmay be provided in addition to the SCUs 11 and the GCU 2. A plurality ofcontrollers (e.g., the SCUs 11 and a plurality of sweep units 50) mayperform an energizing control process in cooperation.

When the energizing control process starts, the SCU 11 sets conditionsfor sweep control (S1). For example, in a case where electric power isoutput from the power supply system 1 to the distribution device 5, theSCU 11 receives a VH instruction signal for instructing a voltage VH tobe output to the distribution device 5, from the GCU 2 as thecontroller. As described above, the SCU 11 sets conditions for sweepcontrol, such as a delay time DL and a period T of a gate signal GS,based on the VH instruction value instructed by the VH instructionsignal, the voltage Vmod of the battery module 30, and the number P ofsweep modules 20 as connection targets to the main line 7 in the sweepcontrol. In accordance with the set conditions, the SCU 11 starts sweepcontrol (S2).

The SCU 11 determines whether a problem (e.g., a failure or degradationof the battery 31) is detected in one of the plurality of batterymodules 30 included in the strings 10 (S4). In this exemplaryembodiment, the voltage detector 35 and the temperature detector 36 (seeFIG. 2) attached to each battery module 30 detects a problem for each ofthe battery modules 30. Signals indicating detection results by thevoltage detector 35 and the temperature detector 36 are output to theSCU 11 through the sweep unit 50 (see FIG. 2). For example, an abnormalvoltage (e.g., a voltage less than or equal to a threshold) is detectedby the voltage detector 35, a problem of the battery module 30 isdetected. In a case where an abnormal temperature (e.g., a temperaturegreater than or equal to a threshold) is detected by the temperaturedetector 36, a problem of the battery module 30 is detected. If noproblem is detected in any of the battery modules 30 (S4: NO), theprocess processes to S10 without any change.

If a problems is detected in one of the plurality of battery modules 30(S4: YES), the SCU 11 causes the indicator 57 to indicate the batterymodule 30 in which the problem is detected (S5). That is, the SCU 11causes the indicator 57 to notify an operator of the battery module 30in which a problem is detected. In an example, the SCU 11 of theexemplary embodiment outputs a signal for indicating driving of theindicator 57, to the sweep module 20 in which a problem is detected.Consequently, the operator is notified of the battery module 30 in whichthe problem is detected.

Next, the SCU 11 excludes the sweep module for which a problem of thebattery module 30 is detected (hereinafter referred to as a “failuresweep module”), from the sweep modules 20 as connection targets to themain line 7 (S6). The SCU 11 excludes the failure sweep module from theconnection targets, and then, sets conditions for sweep control againand continues sweep control under the reset conditions (S7). The SCU 11outputs the forced through signal CSS described above to the failuresweep module, and disconnects the battery module 30 in the failure sweepmodule from the main line 7 (S8). Consequently, with the sweep controlbeing continued as the entire string 10, the battery module 30 in thefailure sweep module becomes replaceable. That is, in replacing thebattery module 30 suffering from a problem, it is unnecessary to stopsweep control of the entire string 10.

The operator can appropriately determine the battery module 30 sufferingfrom the problem by the indicator 57, and can replace this batterymodule 30 by a normal battery module 30. Thus, the possibility oferroneously replacing a normal battery module 30, for example,decreases. As compared to the case of replacing all the batteries 31included in the string 10, the voltage of the battery 31 to be replaced(i.e., the battery 31 in one battery module 30 in this exemplaryembodiment) is reduced to a small degree, and thus, safety can be easilyobtained. In addition, working efficiency can be increased, as comparedto the case of replacing all the batteries 31 included in the string 10.

Thereafter, the SCU 11 determines whether replacement of the batterymodule 30 for which a problem occurs has been replaced or not (S10).That is, in S10, it is determined whether replacement is performed ornot on the battery module 30 for which a problem was detected in S4 andwhich has been disconnected from the main line 7. As an example, in theexemplary embodiment, the voltage detector 35 (see FIG. 2) attached toeach of the battery modules 30 detects that the battery module 30 inwhich the problem is detected has been replaced by another batterymodule 30. The SCU 11 determines that the battery module 30 has beenreplaced in a case where a normal voltage is detected by the voltagedetector 35 after detachment of the battery module 30 in which theproblem was detected. If the battery module 30 in which the problem wasdetected has not been replaced (S10: NO), the process proceeds to S15without change.

If replacement of the battery module 30 in which a problem is detected(S10: YES), the SCU 11 finishes notification of a problem performed bythe indicator 57 for the replaced battery module 30 (S11). Thus, theoperator can easily know that replacement of the battery module 30 wasappropriately completed. The SCU 11 adds the sweep module 20, in whichthe battery module 30 has been replaced, to a connection targets to themain line 7 (S12). After adding the connection target, the SCU 11 resetsconditions for the sweep control, and performs sweep control under thereset sweep control (S13). Thus, with the replaced battery module 30being added, electrification between the string 10 and the distributiondevice 5 is appropriately performed.

A process of adding the sweep module 20 in which the battery module 30has been replaced to connection targets to the main line 7 does not needto be performed immediately after detection of replacement. For example,after the process of adjusting the voltage of the replaced batterymodule 30, the SCU 11 may add the sweep modules 20 to the connectiontargets.

Next, the SCU 11 performs various processes (S15). For example, in acase where the VH instruction value to be output to the distributiondevice 5 is changed, the SCU 11 resets conditions for sweep control,based on the changed VH instruction value. Thereafter, the SCU 11determines whether an instruction for finishing the sweep control isinput or not (S16). If the signal is not input (S16: NO), the processreturns to S4, and the sweep control continues. If the end instructionis input (S16: YES), the energizing control process is finished.

The technique disclosed in this exemplary embodiment is merely anexample. Thus, the technique exemplified in the exemplary embodiment maybe changed. For example, in the exemplary embodiment disclosed above,the voltage detector 35 and the temperature detector 36 (see FIG. 2)detect a problem for the corresponding battery module 30. That is, thevoltage detector 35 and the temperature detector 36 of the aboveembodiment are an example of a problem detector for detecting a problemin each sweep module (in each battery module 30). Alternatively, aspecific configuration of the problem detector may be modified. Forexample, the controller (i.e., the SCU 11 in the exemplary embodiment)may connect the plurality of sweep modules 20 included in the string 10to the main line 7 one by one. The controller may acquire a voltage ofthe battery module 30 included in the connected sweep modules 20, fromthe string voltage detector 26 (see FIG. 1) to thereby detect a problemin each battery module 30.

The voltage detector 35 of the above exemplary embodiment is an exampleof a replacement detector for detecting replacement of the batterymodule 30 in which a problem was detected. The specific configuration ofthe replacement detector may be modified. For example, anattachment/detachment sensor (e.g., a proximity sensor) for detectingdetachment and attachment of the battery module 30 from/to the electricpower circuit module 40 may be provided for each sweep modules 20. Inthis case, the attachment/detachment sensor may be used as thereplacement detector.

FIG. 5 for the above exemplary embodiment shows an example process inthe case where a problem occurs in the battery module 30 included in thesweep module 20. Alternatively, a portion of the technique exemplifiedin the exemplary embodiment is also applicable to a case where a problemoccurs in a component except for the battery module 30 (e.g., thebattery circuit module 40) included in the sweep module 20. For example,in a case where the problem detector (e.g., the temperature detector 48)detects occurrence of a problem in one of the battery circuit modules 40in the sweep modules 20, the SCU 11 may cause the indicator 57 toindicate the sweep module 20 in which a problem in the battery circuitmodule 40 is detected. The SCU 11 may exclude the failure sweep modulein which a failure in the battery circuit module 40 is detected andcontinue sweep control, while continuously disconnecting the failuresweep module from the main line 7. In this case, even when a problemoccurs in at least one of the battery circuit modules 40, the sweepoperation in the string 10 appropriately continues. The operator canappropriately know the battery circuit module 40 in which a problemoccurs, by using the indicator 57.

The process of performing the sweep control in S2 of FIG. 5 is anexample of “first process.” The process of causing the indicator 57 toindicate the sweep module 20 in which a problem occurs in S5 of FIG. 5is an example of a “second process.” The process of continuing the sweepcontrol while disconnecting the failure sweep module from the main line7 in S6 through S8 of FIG. 5 is an example of a “third process.” Theprocess of finishing the instruction by the indicator 57 and resettingconditions the sweep control in S11 through S13 of FIG. 5 is an exampleof a “fourth process.”

Specific examples of the present teaching have been described in detailhereinbefore, but are merely illustrative examples, and are not intendedto limit the scope of claims. The techniques described in the scope ofclaims include various modifications and changes of the above describedexemplary embodiment.

What is claimed is:
 1. A power supply system comprising: a main line; aplurality of sweep modules connected to the main line; a problemdetector; an indicator; and a controller, wherein each of the sweepmodules includes a battery module including at least one battery, and anelectric power circuit module including at least one switching devicethat switches a connection state between the battery modules and themain line between connection and disconnection, the problem detector isconfigured to detect a problem for each of the sweep modules, theindicator is configured to enable instruction of one of the sweepmodules in which a problem is detected, and the controller is configuredto perform a first process of performing sweep control that sequentiallyswitches the battery module connected to the main line among theplurality of battery modules by outputting a gate signal for controllingthe switching device to the electric power circuit module, a secondprocess of causing the indicator to indicate the sweep module in whichthe problem is detected, in a case where the problem detector detectsthe problem in the sweep module, and a third process of continuing thesweep control by excluding the sweep module in which the problem isdetected among the plurality of sweep modules while continuouslydisconnecting, from the main line, the sweep module in which the problemis detected.
 2. The power supply system according to claim 1, whereinthe switching device of the electric power circuit module includes afirst switching device attached to the main line in series and attachedto the battery modules in parallel, and a second switching devicedisposed in a circuit that connects the battery modules to the main linein series, the controller is configured to perform the sweep control bysequentially outputting, to each of the plurality of sweep modules, thegate signal for controlling alternate driving of turning the firstswitching device and the second switching device on and off, at everypredetermined delay time, and in the third process, the controlleroutputs a signal for keeping an on-state of the first switching deviceand an off-state of the second switching device to the sweep module inwhich the problem is detected so that the battery module in the sweepmodule in which the problem is detected is continuously disconnectedfrom the main line.
 3. The power supply system according to claim 1,wherein attachment to the electric power circuit module and detachmentfrom the electric power circuit module are performed using the batterymodule including the plurality of batteries as one unit.
 4. The powersupply system according to claim 1, further comprising a replacementdetector that detects replacement of the battery module in which theproblem is detected by another battery module, wherein the controller isconfigured to perform a fourth process of performing the sweep control,by adding the sweep module in which the battery module is replaced to aconnection target to the main line, and finishing an instruction by theindicator, in a case where the replacement detector detects replacementof the battery module.